Identification of mahogany sliced veneer using handheld near-infrared spectroscopy device and multivariate data analysis

The illegal logging of valuable tree species is mainly motivated by a global market that consumes logs, lumber, veneers, and furniture. The use of objective techniques to identify species and the effects of international initiatives such as CITES rules contributes to controlling trade, exploitation, and smuggling of these products. The anatomical identification of wood veneers is limited due to the loss of several anatomical characters in the production process of the veneers. For this reason, we propose the Near-Infrared Spectroscopy technique associated with chemometric tools for the discrimination of wood veneer of woods with similar general characters: Swietenia macrophylla King (mahogany), Carapa guianensis Aubl. (andiroba), Cedrela odorata L. (cedro), Micropholis venulosa Pierre (curupixá), and Hymenaea coubaril L. (jatobá) using a portable spectrometer.The development of the discrimination models was performed using the PLS-DA (Partial Least Squares for Discriminant Analysis) algorithm. The detection and subsequent exclusion of outliers were performed based on Hotelling T2, Q residuals, and errors in estimating class values. The PLS-DA models showed an efficiency between 96.5% and 100% in the samples’ discrimination among the five forest species. In conclusion, the portable NIRS technology and the PLS-DA models were suitable for the rapid identification and discrimination of the wood veneers.